Effects of Solar UV Radiation on Materials Used in Agricultural Industry in Salta, Argentina: Study and Characterization

Carlos Cadena, Delicia Acosta

National Institute of Chemical Engineering, INIQUI-CONICET, Universidad Nacional de Salta, Salta, Argentina.
National Institute of Non-Conventional Energies, INENCO-CONICET, Universidad Nacional de Salta, Salta, Argentina.

DOI: 10.4236/msce.2014.24001                

Abstract

The current study presents the characterization of three types of materials after exposure to solar UV radiation. The selection of the materials is related to socio-economic aspects and rural activities in the northwest of Argentina (a.k.a. NOA). The objective was to establish a time parameter that allows estimating the durability of the materials according to their use. One of the materials is used as a protective cover (polyethylene film) of greenhouses, which are used for crop cultivation in the area. Another material is used in photovoltaic modules (PVMs), which are used to supply energy in isolated areas and the third material is sunscreen used by people that are exposed to UV radiation during rural activities. Degradation or deterioration of the materials was monitored using different spectroscopic assays: infrared was used to detect any structural changes in the material, X-rays were used for possible changes in the crystalline structure of the material, and spectral transmittance as this property is likely to be affected by changes in the structure of the material. The results showed that degradation of polyethylene seems to be related to the diminution in transparency and the loss of mechanical resistance with increasing exposure time. The decrease in transparency of one of the layers of a PVM caused a considerable decrease in the energy generated, whereas the sunscreens with a low sun protection factor (SPF) rapidly lost their protective properties and changed their photostability properties. Our results revealed a relationship between relative transmittance loss and exposure timse, which allows estimating the stability of different materials.

Keywords

Polyethylene Films, Photovoltaic Modules, Sunscreen Characterization, Degradation Effects, Stability

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	MacKie, R.M. (2000) Effects of Ultraviolet Radiation on Human Health. Radiation Protection Dosimetry, 91, 15-18. http://dx.doi.org/10.1093/ oxfordjournals.rpd.a033186
[2]	Andrady, A.L., Pegram, J.E. and Tropsha, Y. (1993) Changes in Carbonyl Index and Average Molecular Weight on Embrittlement of Enhanced Photodegradable Polyethylene. Journal of Environmental Degradation of Polymers, 1, 171-179.
[3]	Guadagno, L., et al. (2001) Chemical and Morphologial Modifications of Irradiated Linear Low Density Polyethylene (LLDPE). Polymer Degradation and Stability, 72, 175-186. http://dx.doi.org/10.1016/ S0141-3910(01)00024-6
[4]	Tilca, F.D., Cadena, C. and Vicente, M. (2001) Ensayos de films de polietileno de baja densidad para invernaderos expuestos a altas dosis de radiación UV. Revista de la ASADES (Asociación Argentina de Energía Solar), Avances en Energías Renovables y Medio Ambiente-AVERMA, 4, 8, 127-131.
[5]	Tilca, F. (2002) Diseno y construcción de una cámara de ensayos de radiación ultravioleta para estudiar la degradación de materiales poliméricos. Tesis de Maestría en Energías Renovables, Facultad de Ciencias Exactas, UNSa.
[6]	Duffie, J.A. and Beckman, W.A. (2006) Solar Engineering of Thermal Processes. 3rd Edition, Wiley Interscience, New York, 747-775.
[7]	Montero, M. (2003) Evaluación y análisis del comportamiento eléctrico de paneles fotovoltaicos expuestos a la intemperie por más de 10 anos. Tesis de Maestría en Energías Renovables, Facultad de Ciencias Exactas, UNSa.
[8]	Pern, F. and Glick, S. (2000) Photo Thermal Stability of Encapsulated Si Solar Cells and Encapsulation Materials upon Accelerated Exposures. Elsevier.
[9]	McKinlay, A.F. and Diffey, B.L. (1987) A Reference Action Spectrum for Ultraviolet Induced Erythema in Human Skin. CIE Journal, 6, 17.
[10]	González, S., Fernández-Lorente, M. and Gilaberte Calzada,Y. (2008). The Latest on Skin Photoprotection.Clinics in Dermatology,26,614-626. http://dx.doi.org/10.1016/ j.clindeatol. 2007.09.010
[11]	Serpone, N., Dondi, D. and Albini, A. (2007). Inorganic and Organic UV Filters: Their Role and Efficacy in Sunscreens and Suncare Products. Inorganica Chimica Acta, 360, 794-802. http://dx.doi.org/10.1016/j.ica.2005.12.057
[12]	Suarez, H., Acosta, D. and Cadena, C. (2012) Analisis de la capacidad de fotoproteccion de una crema protectora solar aplicada a formulaciones no comerciales. Energias Renovables y Medioambiente, 30, 63-70.